Carburetor



G. HAMMOND Sept. 8, 1936.

CARBURETOR Filed Nov. 14, 1931 Patented Sept. 8, 1936 UNITED STATES PATENT OFFICE CARBURETOR Application November 14, 1931, Serial No. 574,932

16 Claims.

My invention relates to the class of devices that are employed in connection with'internal combustion engines to regulate the relative amounts of combustible fluid and gas used for combustion purposes, and an object of my invention, among others, is to provide a device of this type that shall be simple in construction and particularly eiiicent in operation.

One form of a carburetor embodying my invention and in the construction and use of which the objects herein set out, as Well as others, may be attained is `illustrated in the accompanying drawing, in which- Figure 1 is a view' in side elevation of my improved carburetor.

Figure 2 is a view in central longitudinal section through the same.

Figure 3 is an end View.

Figure 4 is a View in section on a plane denoted by the dotted line 4-4 of Figure 2.

Figure 5 is a view in section on a plane denoted by the dotted line 5 5 of Figure 2.

Figure 6 is a view in section on a. plane by the dotted line 6 6 of Figure 2.

In the accompanying drawing the numeral 'I denotes the case or shell of my improved carburetor which case is generally formed round in cross section and which may be composed of any suitable material, said case having an opening denoted extending therein from end to end and terminat-` ing in a mouth 8 at the inlet end thereof. A supporting ring 9 is screw threadedly engaged with the inlet end of the shell as shown in Figure 2 of the drawing, and a supporting bridge IU is formed preferably integral with the ring and extends thereacross from side to side, said bridge having a hub in its center for a purpose to be hereinafter described.

The body of the case is reduced in diameter toward that end opposite the mouth, the opening along this reduced portion being of cylindrical shape forming a mixing chamber I I, the opening being enlarged between the chamber II and the mouth, this enlarged portion constituting an air inlet chamber I2.

A flanged sleeve I3 is tted in an opening through the side of the case into thek mixing chamber II, and a nipple I4 is extended loosely through said sleeve and extends preferably to a point nearly flush with the inner wall of the chamber I I. The nipple I4 is suitably formed for attachment thereto of a fuel supply tube, a lock nut I5 being employed to retain the nipple in place.

A fuel inlet tube I6 of T shape is screw threadedly engaged with the nipple I4 said tube having a fuel inlet passage ll extending through the stem of the T shaped part and into a needle valve chamber I8 in the cross part of the T shaped inlet tube. A needle valve case I9 is screw threadedly engaged with one end of the cross part of the inlet tube, said case having grooves extending lengthwise along its outer surface and as shown in Figures 2 and 6 of the drawing. The opening in this case is substantially of the size of the chamber I8 in the inlet tube and a needleV valve 2| is supported in the chamber I8, the tapered portion of the valve projecting through a valve opening 22 in the end of the case I9. Said needle valve is provided with guides 23 spaced apart, one of the guides being located near the inner end of the valve, and said guides having notches 24 for the flow of fuel from the passage Il. The needle valve is seated upon a needle valve spring 25 in the chamber I8, said spring being seated against the closed end of said chamber.

An air valve supporting sleeve 26 is screw threadedly engaged With an opening through the bridge I0, said bridge preferably having a hub through which said opening extends. A head 2l is formed on the outer end of the sleeve 26 said head being notched Varound its periphery.

An air valve 28 of a diameter slightly greater than that of the mouth 8 is located within the chamber I 2 so that said valve will rest against a valve seat formed by a lip 29 comprising the boundary of the mouth 8. A valve stem 30 extends from opposite sides of the valve 28 the stem on the outer side of the valve being slidingly tted Within the sleeve 26. Said stem has an opening extending therethrough. The Valvey in the idling position rests against the lower end of the sleeve 26.

A tubular support 3| is screw threadedly engaged with the outer end of the valve stem 30 and supports the outer end of an active section 32 of a needle valve adjusting rod which is slidably mounted in the support 3I. The inner end of the section 32 is loosely engaged with one end of the adjusting'section 33 of said rod, this engagement being such that turning movement of the active section 32 will effect turning movement of the section 33. The end of the section 32 projecting past the end of the tubular part 3l is attened so that it may be t'urned by a wrench to adjust the needle. VThe section 33 is screw threadedly engaged with a vacuum cup support 34 having a recess in one end and a vacuum cup 35 vformed in its opposite end, a threaded hole extending from said recess into said cup which hole is engaged by the adjusting section 33 as above explained. That part of the stem 38 on the inlet side of the valve 28 slidingly ts Within the cup support 34, the latter being therefore guided in its movements on said stem.

An air valve spring 35 surrounds the needle valve adjusting rod Within the opening through the stem 33, said spring thrusting at its lower end against the bottom of the recess in the vacuum cup support and at its opposite end against the tubular support 3l, thereby closing the valve 28. This spring, however, is of such strength as to permit said valve to readily open as may be required under conditions created Within the chamber in the case.

The air valve supporting sleeve 25 having been adjusted to locate the valve 28, said sleeve is held in such adjusted position by means of a lip on the end of a spring retainer 31 secured to the bridge I said lip engaging the notches in the edge of the head 2l hereinbefore referred to.

In order to prevent vibration of the Valve 28 when closed With the spring 36 under minimum tension a damper in the form of a spring 38 is secured to and rises from the bridge lll and presses with its free end against the beveled end of the valve stem 35 to hold it from such vibration.

An important feature of this invention is in the choking mechanism by means of which the yielding resistance to opening movement of the valve is increased for starting purposes. 'Ihe valve therefore not being held rigidly closed may respond to conditions Within the case to admit such amount of air as may be required during choking and starting operations, and the engine will not be forced to take a mixture of substantially unbroken fuel, thereby overloading it which retards free and ready starting and which also is attended with the evil results of carbonization, etc. This choking mechanism which er1- ables an engine to be readily started when cold comprises a choke arm 39 forming part of a choke lever which is extended within the case and may be operated for choking purposes to restrain opening movement of the valve 28 from its closed position, the outer end 40 of said lever located outside of the case being connected for operation by means of a knob or other device conveniently located. This connection includes a pull wire 46 or similar device which is connected to a spring 4l attached at one end to the arm 40, and as shown in Figure 1 of the drawing. In the particular arrangement herein shown the Wire'46 is attached to a guide link 48 abutted against the arm 40. This link may have a shoulder 49 to engage said arm if desired, this engagement being eected by an extreme pull on the Wire 46 and the valve 28 being held rigidly in a closed position, but such a condition will seldom be required and only under abnormal circumstances.

The effect of this construction is to augment the power of the spring 36 for starting purposes and when increased resistance, but of a yielding nature, to opening movement of the valve 28 is required, and the force of this resistance will be governed by the force of the pull on the Wire 46.

The diameter of the chamber l2 is increased as at 4| to an extent to maintain the area of the passage around the valve after the valve has been opened to a certain extent, and this maintains the volumetric eiciency as to the amount of air supplied to the device.

The support 3l is employed for adjusting the tension of the air valve spring 36. The end of said support has a flange, as shown in Figure 2, and this ange is provided with radial grooves that receive the end of the spring, the depth of the grooves being such that the support 3i may be turned by the application of a little force, but the engagement of the end of the spring in the grooves will retain said support against accidental turning movement. The spring is held from turning movement by engagement of its opposite end with a hole in the vacuum cup support 34.

The ribbed valve case I9 forms a guide for the vacuum cup as does also the sleeve hub of the air valve. The air valve is guided by the idling air adjusting sleeve 2'! which is threaded in the central hub of the bridge lil. In other Words, the adjusting sleeve or head 2l and the ribbed cross part of the T-shaped inlet tube form the guide for the air valve and the vacuum cup, the Whole assembly forming a co-acting sliding unit; still, the vacuum cup and sleeve and the air valve may act independently or each other, the one at that time forming a guide for the other.

The adjusting section 33 of the needle valve is held against turning movement, except when force is applied through the section 32 to do this, by means of a block 42 tted into an opening through the support 34, and as shown in Figure 2 of the drawing, said block occupying one end of said opening and one arm 43 of a throttle lever occupying the opposite end, said throttle lever also comprising an actuating arm 44 connected with manually operated means in a manner common to structures of this class. In forming the block 42 a hole is drilled and threaded and the piece is then cut off at the edge of the hole, and a slot is cut into the block from said hole as shown in Figure 4. The outer end of the block is formed to nicely t the hole and the inner end is pinched inwardly. The piece is then hardened and then drawn to spring temper and the hole in which the section 33 engages being now slightly smaller than said section a spring tension upon the threaded portion of the section is obtained sufcient to prevent unintentional turning movement of said section. The needle 2l has a cylindrical portion 45 for a certain distance from its tip in order to avoid an increase in the amount of fuel supplied. In actual practice I have found that a length of about gths of an inch for this cylindrical portion produces extremely satisfactory results. This arrangement causes the richness of the mixture to be maintained While the engine is gaining speed, and when a rich mixture is required. After speed is attained and an increase in the richness of the mixture is not required the cylindrical portion of the needle valve will prevent an increase in the amount of fuel While the amount of air may be increased, this condition being sucient to maintain the velocity acquired by raising the vacuum in the vacuum cup, due to the velocity of the intake air current passing the bell mouthed end of the vacuum cup.

The manner of securing the fuel inlet tube IS in place is an important feature of my invention. It is essential that said tube may be taken out and replaced with assurance that the vertical portion will be located in the center of the case. To accomplish this result the flanged sleeve or plug I3 is made use of as a positioning element. It is threaded into a hole through the boss on the side of the case, as shown in Figure 2, and is provided with lugs 50, as shown in dotted lines in Figure 2, on diametrically opposite sides of its inner edge fitting slotsin diametrically opposite sides of the end of the stem of theV tubeV l5. When the parts are first assembled the sleeve or plug I3 is screwed into the hole in the boss until its flange is seated against the end of the boss or nearly so, the parts being so arranged that in this position of the plug with its lugs 5B engaged in the slots in the end of the stern I6 the gas inlet tube will be in the center of the case.V The plug is then permanently secured in place as by electric welding or brazing and the tube may afterwards be takenout and replaced to be held by the nipple screwed thereinto with certainty that the tube will be located in the center of the case, it being noted that the nipple passes loosely through the plug and is clamped by the nut l5 pulling the end of the stem I6 against the end of the plug I3. While a threaded plug satisfactorily answers my purpose other means for locating the plug in position may be made use of.

Under idling conditions there is a pressure of substantially ten pounds per square inch on the valve 28 tending to open it, which pressure is not overcome by the spring 36, the latter acting to control movements of the valve automatically when otherwise unrestrained. This condition would permit the engine tov race immediately after starting, and therefore to overcome this result I place a resistance to opening movement of the throttle lever arm 44 sufficient to offset the pressure just referred to on the valve 28, this resistance being sufficient to merely overbalance said pressure and prevent the valve from freely opening under starting conditions. In doing this I arrange a post 5I secured to and rising from a supporting plate 52 seated against the flange of the shell l and which plate may be secured by the carburetor retaining screw usually extending through said flange. The post is slotted atits outer end to receive the end of the arm 44, and as shown in Figure 1 of the drawing. A spring 53 surrounds the post and is supported thereby. A bushing 54 with a anged head ts over the stud, the end of the head being rounded to avoid undue friction on the arm under operating conditions. A stop screw 55 projecting through a lip on the arm 44 is positioned to engage the boss on the shell through which the shaft comprising part of the choke lever extends, this screw determining the position of the arm 44 when the valve 28 is fully open with its edge opposite the enlargement 4I of the chamber in the shell. By adjusting this screw the amount of movement of the needle may be determined.

The shaft 56 comprising part of the throttle lever is reduced and threaded at its inner end within the boss supporting it, the arm 43 being secured on the reduced part as by means of a sleeve nut 51 fitting the reduced threaded end of the shaft. To form a key to prevent the arm from turning on the shaft I drill a hole through the shaft and arm as shown in Figure 4, the outer portions of the hole being located one-half in the arm and one-half in the larger part of the shaft. A pin 58 is driven into the hole and may be permanently secured in place if desired. This forms a very convenient and inexpensive way of providing the key.

In accordance with the provisions of the patent statutes I have described the principles of operation of my invention together with the device which I now consider to represent the best embodiment thereof; but I desire to have it understood that the device shown isonly illustrative, and` that the invention may be carried out by other means and applied to uses other than those above set out.

I claimt' Y 1. A carburetor including a shell having. an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake, a vacuum'cup support slidably mounted on a sleeve projecting from said valve, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, means on said support engaged with said needle valve to operate it, a spring located in said sleeve and thrusting ,against said support and against said air intake valve, and means for actuating said support to operate said needle valve and to release pressure on said air intake valve.

2. lA carburetor including a shell having an air intake and a connection for supply of fuel, aV

Valve to control flow of air through said air intake, a vacuum cup support slidably mounted on a sleeve projecting from said valve, a vacuum cup carried by said support, a needle valve within said cup tocontrol admission of fuel thereto, an adjusting screw on said support engaged with said needle valve to operate it, means for turning said screw for adjusting purposes, a spring located in said sleeve and thrusting against said support-and against said air intake valve, and' means for actuating said support to operate said needle valve and to release pressure on said air intake valve.

Y 3. A carb-uretor including a shell having an air intake and a connectiony for supply of fuel, a valve to control flow of air through said air intake, a vacuum cup support slidably mounted in the shell, a vacuum cup carried by said support, valve operating means projecting into an opening in said support, a block located in said opening and having ascrew threaded hole with means for resiliently varying the size of said hole, a needle valve within said cup to control admission of fuel thereto, an adjusting screw in said hole and engaged with said needle valve to operate it, and a spring located in said sleeve and thrusting against said support and against said air intake valve.

4. A-carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake, a vacuum cup support slidably mounted in said shell, a vacuum cup carried by said support, valve actuating means projecting into an opening in said support, a block located in said opening and having a slit extending from one end into a hole through the block to form sides that are spring pressed toward each other, an adjusting screw located in said hole, a needle valve within said cup to control admission of fuel thereto, said needle valve eng/aging the end of said adjusting screw, and a spring located in said sleeve and thrusting: against said support and against said air intake valve to operate it.

5. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air in-` take said valve having a sleeve'projecting outwardly through the end ofA said shell, a vacuum cup support slidably mounted within the shell, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, means on said support engaged with said needlevalve to operate it, a spring located in` said sleeve and thrusting against said support and against the end of the sleeve, and means for actuating said support to operate said naadle valve and to release pressure on said air intake valve.

6. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake and having a sleeve projecting outwardly through the end of said shell, a vacuum cup support slidably mounted on the sleeve projecting from said valve, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, means on said support engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support and against said air intake valve, means at the end of said sleeve for adjusting the tension of said spring, and means for actuating said support to operate said needle valve and to release pressure on said air intake valve.

7. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake, a vacuum cup support slidably mounted within the shell, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, means on. said support engaged with said needle valve to operate it, means on said shell for adjustably ldetermining the position of said air intake valve, a spring located within said air intake valve and thrusting against said support and against said air intake valve, and means for actuating said support to i operate said needle valve and to release pressure on said air intake valve.

8. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake and having a sleeve projecting outwardly therefrom, a vacuum cup support slidably mounted Within the shell, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, means on said support engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support and against said air intake valve, a sleeve adjustably mounted in said shell to determine the position of said air intake valve, the sleeve on said air intake valve projecting through said adjusting sleeve, and means for actuating said support to operate said needle valve to release pressure on said air intake valve.

9. A carburetor, including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake and having a sleeve projecting outwardly therefrom, a vacuum cup support slidably mounted on a sleeve projecting from said valve, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, means on said support engaging with said needle valve to operate it, a spring located in said sleeve and thrusting against said support, means at the end of said sleeve engaged with said spring to vary its tension, and means for actuating said support to operate said needle valve to release pressure on said air intake valve.

10. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake, a vacuum cup support slidably mounted on a sleeve projecting from said valve, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, an adjusting screw mounted in said support and engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support and against said air intake valve, means projecting through said spring and engaged with said screw for rotating it, and means for operating said support to operate said needle valve to release pressure on said air intake valve.

11. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake, a vacuum cup support slidably mounted on a sleeve projecting from said valve, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, an adjusting screw mounted in said support and engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support and against said air intake valve, means projecting through said sleeve and loosely engaged with said screw to rotate it, and means for actuating said support to operate said needle valve to release pressure on said air intake valve.

12. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control ow of air through said air intake and having sleeves projecting from opposite sides thereof, a vacuum cup support slidably mounted on the sleeve on one side, of said valve, a vacuum cup carried by said support, a needle valve Within said cup to control admission of fuel thereto, an adjusting screw mounted on said support and engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support, a spring support adjustably mounted in the end of said Sleeve to adjust the tension of said spring, means projecting through said support and through said sleeve and connected with said adjusting screw to adjust it, and means for actuating said support to operate said valve to release pressure on said air intake valve.

13. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air intake and having a sleeve projecting outwardly therefrom, a vacuum cup support slidably mounted within said shell, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, an adjusting screw in said support engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support, a spring support adjustably mounted in the end of said sleeve and engaged with the end of said spring to yieldingly restrain turning movement of said spring support, means projecting through said spring support and connected with said adjusting screw for operation of the latter, and means engaging said support to operate said needle valve and release pressure on the air intake valve.

14. A carburetor including a shell having an air intake and a connection for supply of fuel, a Valve to control iiow of air through said air intake, a vacuum cup support slidably mounted within said shell, a vacuum cup carried by said support, a needle valve within said cup to control admission of fuel thereto, said needle valve having a cylindrical portion to maintain a constant supply of fuel in a certain opened position, means on said support engaged with said needle valve to operate it, a spring located in said sleeve and thrusting against said support and said air intake valve, and means for actuating said support to operate said needle valve and permit release pressure on said air intake valve.

15. A carburetor including a shell having an air intake and a connection for supply of fuel, a valve to control flow of air through said air inintake and having a sleeve projecting outwardly therefrom, a support movably mounted Within the shell, a needle valve to control flow of fuel to v the shell, a spring located in said sleeve and against said support, a tubular member screw threadedly engaged With said sleeve and having grooves to receive the end of said spring to adjust its tension, and means for yieldingly connecting the adjusting member and spring to yieldingly restrain turning movement of the former.

16. A carburetor including a shell, means for supplying fuel to said shell, a lever for controlling said supply, said lever including a shaft having a reduced end, an arm placed upon the reduced end of said shaft by endwise movement of said shaft through a hole in said arm, a pin engaging a notch in said arm to hold it against rotation on said shaft, a sleeved nut engaged with the screw threaded reduced end of said shaft through a hole in said shell to hold said arm in place and means for operating said shaft.

GRANT HAMMOND. 

